1. Technical Field
The present invention relates generally to robotic tool changing systems which are compatible with one of the most conventional type of robot end-effectors or "hands" used in industry at the present time; and, more particularly, to a simple, highly flexible, yet effective and versatile changeable tooling system for robotic end-effectors which permits the opposable, generally parallel, vise-like "fingers" of an otherwise conventional robotic end-effector--i.e., "fingers" which are capable of being moved towards one another in a closing operation to grasp, retain and manipulate the particular tool to be employed, and providing all motive power and/or utility connections (electrical, pneumatic, hydraulic and/or material dispensing such as adhesive or the like) for such tool; or, to move away from one another in an opening operation to release the particular tool previously used prior to grasping yet another different type of tool--to: (i) acquire; (ii) align and grasp; (iii) identify the requisite motive power and/or utility connections required to operate the particular acquired tool and to render such specifically identified power and/or utility connections operative; and (iv), to manipulate such tool through its normal operating cycle, all without the need for human intervention. Thus, the exemplary changeable tooling system for robotic end-effectors employing features of the invention permits the employment of tool alignment mechanisms at the tool/"finger" interface and a plurality of generic electrical and/or fluid interconnections at such interface, with all tool identification circuitry and electrical and fluid utility lines required to identify and operate a wide range of different types of tools being permanently installed in, and routed internally through, the robot arm and/or end-effector so as to permit any given tool--whether it be electrically powered, fluid powered (pneumatic and/or hydraulic), or coupled to two or more different types of motive power and/or utility lines--to be acquired, identified, coupled to the applicable utility line(s) uniquely required for that tool, and operably manipulated, all without the need to make any change, modification or adjustment to the robot end-effector and/or without the need to replace the end-effector at the "wrist level" with a different end-effector uniquely designed for coupling to the next specific tool to be employed.
2. Background Art
With the rapidly increasing trend towards industrial mechanization and automation, a wide range of different types of robotic tool manipulators have been developed, particularly during the last few decades. One of the most common types of robotic tool manipulating devices, and the one which has found relatively widespread commercial acceptance in a wide range of different industrial applications, is a robotic tool manipulator of the type having an end-effector or "hand" employing a pair of opposable, generally parallel, vise-like, grasping "fingers" which are capable of being moved towards one another to grasp and retain a tool or other object therebetween for operable manipulation thereof; and, upon completion of the operational cycle for that particular tool or object, to be moved away from one another so as to release the tool or object. In general, however, each different tool to be employed will have its own unique set of operating requirements such, for example, as interconnectability to one or more electrical utility lines for providing motive power, fluid utility lines for powering the tool and/or for controlling metered discharge of materials to be discharged and employed by the tool, etc.
As a consequence of the varying and specific utility requirements for each different tool employed in a particular operational routine to be carried out on a given workpiece and/or on a plurality of successively presented workpieces, it has been found that robotic tool manipulators of the type most commonly used today--e.g., robots having opposable, vise-like, finger-type end-effectors--generally require that the specific end-effector be custom designed for compatibility with only one specific tool or, perhaps, a few similarly designed tools. Thus, when faced with an operational task requiring the use of a significantly different type of tool and/or requiring coupling to a different utility line or combination of utility lines, the user must resort to either a different robotic tool manipulator or, alternatively, the specially designed end-effector or "hand" of the manipulator must be removed and replaced with a different end-effector specifically designed for compatibility with the next type of tool to be employed. Generally, this requires human intervention and a relatively complex manual operation where one end-effector is unbolted and disconnected from the robot arm at the "wrist level" and replaced with a different end-effector specially designed for coupling with the new tool to be employed. Not only is such an operation time-consuming and labor-intensive but, moreover, it can require significant capital investment in terms of stocking a plurality of specially designed end-effectors each of which has only a limited range of use.
In addition, where the robot arm is required to accommodate a wide range of different types of end-effectors, the manipulator generally requires the provision of a plurality of electrical and/or fluid utility lines that can be selectively defined and controlled, and externally coupled to the various tools employed, often resulting in systems wherein the utility lines impinge upon the tool work space with the consequent risk that such lines will become entangled with the workpiece, fixture and/or with the robot arm, end-effector or tool carried thereby. Moreover, when employing special purpose custom designed end-effectors, it has been found that such devices, while highly effective for use with the particular tool for which they are designed, often are incapable of grasping and manipulating other tools or objects. And, of course, when the robots require a "wrist level" tool change, the robot will not, at least in most instances, have a useful end-effector without a special purpose tool installed therein.
One prior patent of general interest is U.S. Pat. No. 4,310,958--Balaud et al. Thus, this patent discloses an exemplary production line automatic machine or robot having the ability to be used with a plurality of successive tools. To accomplish this, the robot employ rather complex special purpose bearing plates adapted to be engaged with complementary mating bearing plates on the particular tools to be subsequently employed. Rather than an end-effector employing opposable "fingers", the patentees disclose the use of coupling arrangements including pivotable flanges, axially movable rods, and rotating screws. No provision is made for tool "identification" and/or selection of an appropriate one or more of a plurality of power and/or utility lines.
In U.S. Pat. No. 4,046,263--Cwycyshyn et al, the patentees disclose a multi-axis robot for selectively receiving and holding one of at least two different work tools. Again, the tool changing system is suitable only for use with tools having custom designed mating couplings; and, no provision is made for tool identification and redefinition of a plurality of interconnectible power and/or utility lines.
In U.S. Pat. No. 4,165,116--Baudoin et al, the patentees describe grasping apparatus for the tongs of a remote manipulator which enables the manipulator to handle objects which are otherwise difficult to handle with conventional robotic grippers. To this end, the apparatus includes, in essence, a glove into which the robotic gripper tongs are inserted so as to provide positive registration between the gripper tongs and special purpose objects.
Other patents of miscellaneous interest include: U.S. Pat. Nos. 3,551,005--Brun and 3,635,184--Liautaud, both of which disclose underwater connectors; U.S. Pat. Nos. 3,917,335--Jones and 4,360,230--Wood et al, which disclose gripper mechanisms for handling and extracting nuclear fuel rods; and, U.S. Pat. Nos. 3,171,327--Williamson, 3,254,567--Daugherty, and 4,057,881--Stephens, which disclose various types of tool gripper mechanisms suitable for use with machine tools such as turret-type lathes and the like. U.S. Pat. Nos. 3,963,271--Sugino et al and 4,132,318--Wang et al, and European Pat. Application No. 81303347.9 published on Mar. 2, 1982, under Publication No. 0045174, assigned to the applicant Fujitsu Fanuc Limited, are of general interest for their disclosures of opposable finger-type end-effectors. Several of the foregoing published documents describe, and are representative of similar descriptions of, such conventional robotic elements as alignment pins, electrical contacts, locking mechanisms, sealing mechanisms, and the like--viz., features which, of and by themselves, are common to robotic tool interface designs.
But, the foregoing patents and/or publications fail to describe or suggest a simple, effective, highly versatile, generic robotic end-effector of the vise-like opposable finger type capable of handling virtually any type of object irrespective of the object's compatibility or lack of compatibility with alignment, motive power and/or utility interconnections, as well as a wide range of different special purpose tools each having their own unique utility requirements and wherein the tool changing system includes provision for identifying the specific tool grasped and automatically selecting, defining, and rendering operative, only that particular utility line or those particular utility lines required for proper operation of that specific tool; and, then, only when the tool is properly aligned and grasped by the end-effector fingers.